Given: A thin-walled square tube with median edge dimensions, a X a, wall thickness, t, and a longitudinal slot of negligible width in therms of circumference.
Find: Compare the torsional strength and stiffness of this square tube with and without the longitudinal slot (use open section membrane analogy vs. shear flow)
In other words
1. the ratio of tao (unslotted)/ tao (slotted)
2. the ratio of fee (unslotted) / fee (slotted)